When driving your car, your engine runs your alternator. The alternator then charges your battery and is responsible for running the electronics in your car while it’s running. So not only does your alternator make sure that the car runs and has power, it also makes sure that when you turn it off, your battery can turn it all back on again.

What is an alternator?

It’s a pretty neat piece of kit really! An alternator gets its name from the current it generates - alternating. It generates this current from the belt spinning the electromagnet inside the housing. As this electromagnet spins, it sends a charge to the stators. This is a DC current and the rectifier converts this to AC, the regulator then sends the right amount out so your car can use it. It all sounds really complicated and it is. 

Why do you need an alternator?

Without an alternator your car won’t run for long. It needs the electricity to run all the essential components of the engine. If your engine can’t run then you’ll be left to walk. The alternator makes sure the battery is charged and then takes over the electricity supply as soon as the motor is running. It is an essential part of your engine. 

How to tell if you need a new alternator

It’s usually indicated by your battery always being dead when you try to start the car. It usually means that the alternator is on its way out. If your lights both inside and outside the car are dim or flickering while driving, it can also mean that the alternator is struggling. You may get a warning light on the dash telling you that you charge is low or a battery light comes on. 

How is an alternator replaced?

The mechanic will run the engine and check the output from the alternator as well as the belts powering the alternator. This ensures that it really is just the alternator and not a problem with the car's electrics. If it is the alternator, then the terminals will be disconnected from the battery and the belt tensioner will be loosened. The alternator will be unbolted from the engine and swapped for a new one. The new one is bolted up and the belt connected to. The terminals will be connected to the alternator and the battery will be reconnected. The engine will be started and run to check the output charge from the new alternator. 

How much does a new alternator cost?

The alternator is an expensive part, the installation is not too tricky however. 

Expect the prices for a new alternator to start around $350 and go higher than $1100, depending on the difficulty to access the alternator and the cost of the new one.

How often do I need an alternator replaced?

Only when it starts to fail. Oftentimes it’s just the belt or connectors that’re playing up and they are an easy fix. 

Is a broken alternator unsafe?

It can be. If your car loses power while you’re driving you may lose power steering, power brakes and other important pieces of equipment. It is usually just a big inconvenience, you want your car to start when you need it to and a bad alternator can stop this from happening.

You can find a mechanic near me with My Auto Shop